The present invention relates to a method of and an arrangement for producing threads on workpieces.
More particularly, the present invention relates to a method of producing threads on workpieces with an axial threaded roll head provided with two threaded rolls arranged on a rotary disk of a numerically controlled automatic lathe, as well as an arrangement for performing the method.
It is known for rolling a thread on a workpiece to axially displace the threaded roll head and after rolling of the thread to withdraw the threaded roll radially from the workpiece with the aid of eccentrics and a mechanism by which the rolls are radially turned from the workpiece. After this, the roll head is axially moved back. Subsequently the threaded roll head must be shut.
In accordance with another known method of producing threads, the threaded rolls after rolling of the thread rotate back, so that no turning is needed. For the use of computer numbered controlled automatic lathes with a transverse axial and height-adjustable rotary disk on a carriage for receiving a threaded roll head or automatically controlled rotary machines of another type, the known axially threaded roll heads are not suitable since they require considerable efforts to shut again the threaded roll head after the radial turning of the threaded rolls, for conducting a further working step. A further disadvantage is that it is not possible to roll on a workpiece a thread, when the workpiece is clamped in a lathe between two points so that the axial displacement is not possible.